The effects of commonly used ophthalmic drugs on the fluid permeability of the isolated ciliary body will be examined, with the determination of the site of action being defined as alpha- or beta-adrenergic. Dose response curves will be generated to determine the effects of the drugs. Drug effects will also be studied in the living rabbit eye by measuring aqueous humor formation rate as well as pseudofacility using the inulin dilution method at two different intraocular pressures. Using these two techniques it will be possible to determine the locus of action of drugs in the eye, since the in vitro technique is not influenced by blood flow but the in vivo eye is influenced by blood flow. Drug effects will be described, therefore, in terms of both in vitro and in vivo responses. Further delineation will be made of the effects of drugs on the phospholipid metabolism of the iris alpha-receptor which has been shown to be influenced both in vitro and in vivo by alpha-adrenergic agonists. The biochemical events are correlated with changes in the receptor site in the muscle membrane. BIBLIOGRAPHIC REFERENCES: Green, K. 1977. The ocular effects of cannabinoids. In "Current Topics in Eye Research" J.A. Zadunaisky and H. Davson, eds. Academic Press, New York, in press. Green, K., Griffin, C.R. and Bowman, K. 1977. Interaction between osmotic and hydrostatic pressures on water flow across the isolated ciliary epithelium, in press.